It probably wasn't very Sentinel-like of him, but a part of Harry was glad he'd had to leave Hermione behind in the chess chamber - even if it meant he lost track of her heartbeat, the scent of her hair.
Not that he didn't want her beside him, far from it. He just knew who they were going to face at the end of this tunnel of traps and preferred that she never got anywhere near him.
Being on the same planet was too close, as far as Harry was concerned.
So he'd made her as comfortable as he could on the floor of the chess chamber, confirmed that the troll was, in fact, dead - though he hadn't told Hermione that part, either. As his Guide, his partner in life and battle, she was entitled to know all he knew, but … not just yet.
He justified it to himself because they weren't fully bonded yet, but he'd have to tell her the full truth, and why he'd kept it from her, as soon as this was over.
The row of potions and accompanying logic puzzle in the room beyond the troll - and especially the black flames barring the door before him and the purple fire that sprang to life in the door behind him - made him grateful for all of Uncle Ben and Alpha Holmes' lessons in meditation and how a psionic bond worked.
Those lessons had helped him relay the logic puzzle to Hermione, and after a few minutes of silence while she thought, she told him the correct bottle.
Before he'd drunk the potion it contained, Harry told her he wasn't sure when he'd contact her again. Lacking a complete bond made contacting her psionically far more challenging than it should be, and he figured he'd need all his wits about him to face what was to come.
She'd agreed, and they'd let the contact fade. Only after it faded did Harry acknowledge that he also hoped Hermione never, ever, saw him in a feral battle drive, and if anyone or anything was likely to provoke such a response, what awaited him at the end of the challenges would.
So he picked up the correct potion, the smallest bottle on the table, uncorked it, and drained it in one long swallow.
Ice seemed to flow through Harry's body - probably not surprising, if it protected him against fire. He put the bottle down and strode through the flames.
It was an odd sensation, watching flames licking at his body and not feeling anything except a slight warmth. For a moment, even his Sentinel's senses were filled with black fire, and then he was on the other side, in what might be the last chamber.
The smell had told him who would be there even before he emerged.
"Hello, Professor Quirrell."
The turbaned professor met his appearance calmly. "I wondered whether I'd be meeting you here, Potter."
"It was never a question," Harry said. "Not when I realized why you stink so badly of garlic."
"What do you think you know?" Quirrell demanded.
Harry shrugged. "Garlic's one of the few scents that can cover up the stench of decay. There're only a few things that come close, and garlic's the most common."
While he spoke, Harry had been evaluating the terrain and opponent before him. The room itself was bare except for a mirror on a stand, which meant there was no cover for Quirrell - nor for him. His enhanced senses didn't pick up any active magic - no shields or traps for the unwary - so it looked like any confrontation would be one on one. Just the way a Sentinel liked it.
Quirrell snorted. "Too nosy for your own good. Be a good lad, and wait quietly while I examine this most interesting mirror."
Even as Quirrell's hand began to move, Harry felt magical currents swirling in the room.
Training with the Alpha Sentinel of the UK - not to mention those who served under him - had its advantages. Harry was dodging forward and to his left before Quirrell's spell finished casting.
Good thing, too - a bunch of ropes launched at where he'd been standing. If he'd still been there, he would've been tied up like Mum's Sunday roast.
Harry's wand slipped into his hand, and he was sorely tempted to destroy the mirror - Quirrell shouldn't be allowed to take something he wanted that badly - but Quirrell cursed and aimed another spell his way.
For the next little while, Harry was too occupied with dodging to cast spells of his own, but his movement paid off when he was finally close enough to the mirror to use it as a barrier between him and Quirrell.
"Very good, Potter," Quirrell said, sounding impressed. He wasn't stuttering - and, Harry realized, he hadn't been since they'd been in this room together. "Perhaps there's some truth to the stories that you defeated Lord Voldemort when you were a baby."
"Maybe there is," Harry said, grinning a predator's grin. "And if I could defeat him as a toddler, just think what I can do to you now."
To his surprise, Quirrell laughed. "You think you only face me, boy? Lord Voldemort is on my side."
"He's not here now, is he?" Harry taunted. "It's just you."
A thin, high-pitched voice came from Quirrell - no, from behind Quirrell. "Show him."
Harry blinked, and surprise kept him in place, despite the target of opportunity Quirrell presented as he turned his back.
Quirrell unwrapped his turban, and with each layer, the scent of garlic grew a little less, and the scent of decay grew a little more.
The scent made Harry's stomach clench, and he fought the urge to vomit, instead lowering his scent-perception. Quirrell was still unwrapping his turban - he seemed to be drawing out the suspense, rather than getting on with business.
That was all right - Harry could get down to business instead.
"Petrificus Totalus."
Quirrell leapt aside, showing reflexes Harry hadn't expected, whirling to face Harry in the same move. Then he jumped into the air - no, he took off and flew straight at Harry.
"Stupefy!" Harry shouted, and again Quirrell dodged the spell.
Then his hands were around Harry's neck. Harry fought to pry them away and lost his wand as he struggled, but Quirrell had gained force through determination, it seemed, or else Harry hadn't yet come into his full strength, because Quirrell's fingers stuck fast.
Quirrell screamed. "My hands! Master, my hands!"
"Kill him," responded the thin, high voice. "Kill Harry Potter!"
Harry kicked and squirmed, trying to find any kind of leverage, fighting for the slightest breath to cast a spell, even as black spots clouded his vision and Quirrell kept screaming.
Then Harry was gasping for breath, through no action of his own. Quirrell had jerked away and sat staring at his hands, which were red and blistered and stank of burning flesh.
"My hands," Quirrell moaned, even as that thin voice shouted, "Kill him!"
While Quirrell fumbled for his wand, Harry found his own.
"Incarcerous!" Harry thrust his wand at Quirrell and ropes sprang from the air to bind him. Harry repeated the spell twice more, just to be sure.
Cautiously, he circled his opponent, his wand ready. Quirrell's turban had come all the way off during their wrestling, and Harry was curious to see what he'd been hiding under it.
Harry's nose crinkled at the scent that, this close, was overwhelmingly pungent despite his reduced sense of smell.
Quirrell was bald and … he had a second face emerging from the back of his head.
"What the…"
"See what I have become?" the face said. "Mere shadow and vapor … I have form only when I can share another's body … but there have always been those willing to let me into their hearts and minds…."
"Harry!"
Hermione's shout cut off whatever else the face might have said, and Harry looked up to see her running at him. Her feet made no noise - Silencing Charm?
He took a step forward and braced for impact just as she threw her arms around him. He inhaled her scent, letting his sense of smell return to normal levels as he did.
The inhale also told him that Uncle Ben had cast the Healing Charm on her leg as well as the Silencing Charm.
He raised his head from where he'd buried it in her neck and saw not just Uncle Ben, but Dad, Alphas Holmes and Mallory, Gran Ran, a man Harry didn't know who must be related to Hermione somehow, judging by his hair, scent, and disapproving expression. Flanking them were four men in uniforms Harry didn't recognize.
"Are you okay, Harry?" Dad asked.
Harry nodded. "I dodged all his spells and got him with a Full Body-Bind Curse."
"What?" Hermione jerked back from their embrace to glare up at him. "How do you know that spell already?"
"You mean you don't?" Harry asked with a grin. At her frown, he said, "I grew up with magical coppers as parents. And I don't mean Aurors. I mean coppers who have magic. And I'm an Alpha Sentinel who came online way too young. I've been training as far back as I remember."
"You're teaching me," Hermione declared. "I want to learn all the spells!"
"Sure. But first - Gran," Harry said, "I think you're needed." He jerked his head toward Quirrell.
Gran arched an eyebrow at him but came forward, two of the uniformed men flanking her at the Alpha Sentinel's nod, and studied Quirrell, who sat quietly.
The face on the back of his head, though, continued to go on about his greatness and how he would come back.
Gran ignored him and her wand danced in intricate patterns as she evaluated first Quirrell, then the face on the back of his head and then finally, worryingly, Harry himself.
"Well." She cast two more times, one at Quirrell's face and one at the other face, and these Harry recognized as Stunning Spells, if only because Quirrell appeared to pass out. Then she turned to face the rest of them, her expression grim. "I believe the spirit possessing him is-"
"Voldemort," Harry finished with her and, when they all looked at him with varying degrees of horror or interest, added, "He said I wasn't facing only him, that Voldemort was on his side."
Alpha Guide Holmes scowled. "Right. What do we do about that?"
"You? Nothing," Gran said. "Because you aren't magical, and this requires a magical solution."
Uncle Ben groaned. "Another exorcism."
"And then some," Gran agreed.
"What more?" Dad asked.
"When I cleansed Harry ten years ago," Gran said, "I thought it was a mishap of some kind, probably to do with whatever protections James and Lily Potter put on him. A magical accident that lodged a portion of someone's soul in another person would be spectacularly improbable, mind you - but it was the only explanation I had."
"You have another one now?" Alpha Holmes asked.
"I think this bloody tosser-" Gran jerked her chin at the back of Quirrell's head "-was stupid enough to split his soul. More than once."
Alpha Sentinel Mallory and the man who was probably Hermione's father both looked torn between being horrified and being nauseous.
"That's … possible?" Probably-Mr.-Granger asked.
"Only through a complex ritual," Gran told him. "There have only been a few documented cases of it actually being done. I believe this is another."
"Again - what do we do about it?" Alpha Holmes asked, ever practical.
"I'll assemble a team - people I've worked with before and whose discretion can be relied upon," she said. "We'll exorcise him and use this fragment of Voldemort's soul to determine if there are others and how many, as well as where they may be located. Then we'll obtain them and destroy them in ritual."
Alpha Sentinel Mallory cleared his throat. "I don't know if it's a result of the rings you gave us that let us see the magical world or something else, but all of my instincts are saying he's a threat to my Tribe."
"He is," Harry said, and the others turned to him. "He's a threat to every Tribe - not just here in Britain, but around the world. He wants to reshape society, you see, and when has anyone who wanted to do that stopped with their own? They've always had to be stopped by force."
"I want to attend whatever rituals you perform," Alpha Mallory told Gran. "To observe, at least. My instincts won't settle until I see him dead myself."
"Will that be enough?"
Hermione's quiet question made Harry turn to her. "What do you mean?"
"I mean-" she took a breath and met his gaze before addressing the Alpha pair "-that it wasn't just Voldemort, was it? He had followers, and an inner circle that he branded with the Dark Mark - not that I know what that is, the books don't say - but there are still people who would gladly help him. Quirrell was one, and nobody's even checked to see if he has the Dark Mark."
Dad exhaled sharply. "Quite right, Guide Granger." He aimed his wand at Quirrell. "Diffindo."
Both sleeves of Quirrell's robes fell down, exposing his arms - arms that were free of any mark, dark or otherwise.
"That's good to know," Dad observed.
"But it's only a start," Alpha Holmes said. His calculating expression was something Harry expected from a Sentinel, not a Guide.
Alpha Mallory swore under his breath. "I'm going to have to dress for tea again, aren't I?"
"Her Majesty appreciates how you look in a bespoke suit," Holmes returned mildly.
"She appreciates Bond more," Mallory shot back. "Fine. Tea it is - but we see this through together, Guide."
"As always, Sentinel," Holmes said. "But first, let's find out why they were so interested in this mirror."